We are interested in the immunologic abnormalities manifested in several human diseases, including the rheumatic diseases, allergic diseases, malignancies of the lymphoid system, and immunologically mediated dermatologic disorders. The approach to the conditions under study (notably psoriasis) has involved the definition of abnormal immune function as defined by either serum immunoglobulin or lymphoid cellular abnormalities. For these studies we utilize serum products or cells of the immune system or of the skin.